Casing pipe repairing tool

Abstract

The invention discloses a sleeve repairing tool which comprises a center pipe, an expansion pipe, a locking mechanism, an expansion cone, a plurality of annular plugs and a cylinder body. The multiple annular plugs are arranged outside the center pipe in a sliding and sleeving mode and distributed in the axial direction of the center pipe at intervals. The cylinder body is arranged outside the central pipe in a sleeving mode, annular ports are formed by the two ends of the cylinder body and the central pipe, each annular port is plugged by an annular plug, a hydraulic cavity is defined by the central pipe, the two adjacent annular plugs and the cylinder body located between the two adjacent annular plugs, the hydraulic cavity comprises a first sub-cavity, and a second sub-cavity is formed by the first sub-cavity and the second sub-cavity. The first sub-cavity is communicated with a pipe cavity of the central pipe through a first liquid passing hole formed in the central pipe; among the plurality of annular plugs, the lowermost annular plug is connected with an expansion cone, and the expansion cone is slidably arranged on the central pipe in a sleeving manner; the reducing section of the expansion pipe is located below the expansion cone, and the expansion pipe is connected with the central pipe through a locking mechanism in a locking state.

Description

Technical Field

[0001] This invention relates to the field of drilling repair equipment design technology, and in particular to a casing repair tool. Background Technology

[0002] As the development of old oilfields in China matures, casing damage in old wells is becoming increasingly common. To ensure the continued normal production of these old oilfields, it is necessary to repair the damaged casing. Current repair processes typically involve first using tools (such as milling taps) to repair the damaged area, and then, once the damaged casing reaches a certain diameter, using casing repair techniques to restore the integrity of the wellbore. Compared to traditional chemical repair methods such as cementing, casing patching technology, as a mechanical sealing and repair method, offers high pressure resistance, high strength, and the ability to effectively repair the pressure-bearing capacity of the wellbore, making it a widely used casing repair technology.

[0003] However, the casing repair technology in related fields essentially involves lining the damaged casing with a new casing section. But the new casing needs to be connected to the casing repair tool via a sealing thread before it can be lowered to the repair location.

[0004] To ensure the stability of the connection between the new casing and the casing repair tool, the new casing requires a larger wall thickness to accommodate deeper sealing threads. The new casing is lined inside the damaged casing, thus forming a new wellbore with the undamaged casing in the original wellbore. Furthermore, the inner diameter of the new wellbore at the new casing is significantly reduced due to the larger wall thickness of the new casing.

[0005] Because some older wells require the insertion of large-sized tools to complete subsequent operations and extraction, there are requirements for the inner diameter of the new wellbore formed after repair. However, the casing repair technology used in related technologies can lead to an excessive reduction in the inner diameter of the new wellbore, which limits further operations and extraction of the older well, and thus is detrimental to the efficient production of the old oilfield. Summary of the Invention

[0006] This invention discloses a casing repair tool to solve the problem that, in related technologies, casing repair tools can cause a significant reduction in the inner diameter of the wellbore after repairing damaged casing.

[0007] To address the aforementioned technical problems, the present invention discloses the following technical solutions:

[0008] This invention discloses a casing repair tool, which may include a central tube, an expansion tube, a locking mechanism, an expansion cone, multiple annular plugs, and a cylinder; wherein:

[0009] The plurality of annular plugs are slidably sleeved outside the central tube and are spaced apart along the axial direction of the central tube;

[0010] The cylinder body is sleeved outside the central tube, and both ends of the cylinder body form annular ports with the central tube. Each annular port is blocked by an annular plug. The central tube, two adjacent annular plugs, and the cylinder body located between two adjacent annular plugs form a hydraulic cavity. The hydraulic cavity includes a first sub-cavity, which is connected to the lumen of the central tube through a first liquid passage hole opened on the central tube.

[0011] Among the plurality of annular plugs, the lowest annular plug is connected to the expansion cone, which is slidably fitted onto the central tube;

[0012] The reduced diameter section of the expansion tube is located below the expansion cone, and the expansion tube is connected to the central tube through the locking mechanism in a locked state;

[0013] When a working fluid at a preset pressure is introduced into the lumen of the central tube, the working fluid can enter the first sub-cavity through the first fluid passage and push the plurality of annular plugs and cylinders downward along the central tube, thereby driving the expansion cone to extend to the reduced diameter section and expanding the reduced diameter section to tighten and fix it to the inner wall of the sleeve to be repaired.

[0014] In one embodiment, the central tube includes multiple central tube segments and connecting sleeves. Two adjacent central tube segments are fixedly connected to both ends of the connecting sleeve by threaded engagement. Two adjacent central tube segments, two adjacent annular plugs, and the corresponding cylinder body form the hydraulic cavity.

[0015] In one embodiment, the outer wall of the connecting sleeve is provided with a support protrusion, which is located in the corresponding hydraulic cavity and slides in cooperation with the inner wall of the corresponding cylinder.

[0016] In one embodiment, the support protrusion is an annular protrusion extending circumferentially along the connecting sleeve, the annular protrusion dividing the hydraulic cavity into a first sub-cavity and a second sub-cavity located above the first sub-cavity, and the annular plug or the cylinder body located above the second sub-cavity is provided with a second liquid passage hole communicating with the second sub-cavity.

[0017] In one embodiment, the support protrusion engages with an adjacent annular plug in a first direction, and the support protrusion engages with another adjacent annular plug in a second direction, wherein the first direction is opposite to the second direction.

[0018] In one embodiment, the support protrusion and the connecting sleeve are an integral structure.

[0019] In one embodiment, there are at least three annular plugs and at least two cylinders, which are spaced apart along the axial direction of the central tube. Multiple pairs of adjacent annular plugs block the annular ports at both ends of the cylinders located between them, forming multiple hydraulic chambers. The central tube has multiple first liquid passage holes that are respectively connected to the multiple hydraulic chambers.

[0020] In one embodiment, the locking mechanism is a hydraulic anchor.

[0021] In one embodiment, the sleeve repair tool further includes a connector, which is fixedly connected to the central tube by a threaded connection.

[0022] In one embodiment, the plurality of annular plugs are fixedly connected to the corresponding cylinder body via threaded connection.

[0023] The technical solutions disclosed in the embodiments of the present invention have the following technical effects:

[0024] The casing repair tool disclosed in this invention repairs damaged casing by replacing it with an expanded expansion tube. The expansion tube is connected via a locking mechanism mounted on a central tube located inside the expansion tube. In this configuration, the expansion tube does not require threaded connection with other components of the casing repair tool during lowering, eliminating the need for a large wall thickness to ensure the stability of the threaded connection. This structure allows for a smaller wall thickness in the expansion tube. After the expansion tube expands and tightens against the inner wall of the damaged casing, it forms a larger inner diameter, preventing a significant reduction in the inner diameter of the newly formed wellbore at the expansion tube. This is particularly beneficial for older wells requiring the insertion of larger tools for subsequent operations and mining. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the sleeve repair tool disclosed in an embodiment of the present invention.

[0026] The components in the diagram are labeled as follows:

[0027] 10-Central pipe, 11-Central pipe section, 12-Connecting sleeve, 13-Supporting protrusion,

[0028] 20 - Expansion tube, 21 - Reduction section

[0029] 30-Locking mechanism,

[0030] 40-Expansion Cone

[0031] 51-Annular plug, 52-Cylinder block, 60-Connector, 70-Conical seat,

[0032] 01-Hydraulic cavity, 011-First sub-cavity, 012-Second sub-cavity, 02-First liquid passage hole, 03-Cavity, 04-Second liquid passage hole. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] The technical solutions disclosed in the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Please refer to Figure 1 This invention discloses a casing repair tool. The disclosed casing repair tool is used to repair damaged casing inside a wellbore. The casing repair tool disclosed in this invention includes a central tube 10, an expansion tube 20, a locking mechanism 30, an expansion cone 40, multiple annular plugs 51, and a cylinder 52.

[0036] The central tube 10 is the main frame of the casing repair tool. The central tube 10 is used to connect with the lowering equipment (such as drill pipe), thereby realizing the connection between the entire casing repair tool and the lowering equipment. Driven by the lowering equipment, the entire casing repair tool can be lowered to a preset position, thereby performing subsequent repairs on the damaged casing at the preset position.

[0037] The expansion tube 20 is a tubular component that needs to be expanded and tightened onto the inner wall of a damaged casing to replace it. After being tightened, the expansion tube 20 ultimately serves as a new casing, fitting with other undamaged casings within the original wellbore to reconstruct the wellbore. In this embodiment of the invention, the expansion tube 20 is a stepped tubular component, including a reduced-diameter section 21. The reduced-diameter section 21 has a smaller diameter than other parts of the expansion tube 20 and is the portion of the expansion tube 20 that will be expanded and tightened onto the inner wall of the damaged casing.

[0038] It should be noted that after the reduced diameter section 21 expands, it tightens onto the damaged casing, thereby covering the damaged area and ensuring the integrity of the newly formed wellbore. The expansion tube 20 is also fitted outside the central tube 10.

[0039] The locking mechanism 30 has a locked state and an unlocked state. The locking mechanism 30 is fixed to the central tube 10. The locking mechanism 30 is used to connect the expansion tube 20 to the central tube 10. Since the expansion tube 20 is sleeved outside the central tube 10, and the locking mechanism 30 is fixed to the central tube 10 and connected to the expansion tube 20, it can be considered that the locking mechanism 30 is also located inside the expansion tube 20.

[0040] The locking mechanism 30 is fixed at a lower position of the central tube 10. In one embodiment, the locking mechanism 30 can be fixed at the bottom end of the central tube 10. It should be noted that, in this embodiment of the invention, the central tube 10 has a top end and a bottom end, the top end and the bottom end of the central tube 10 are opposite ends of the central tube 10, and the bottom end of the central tube 10 is lower than the top end of the central tube 10.

[0041] Specifically, when the locking mechanism 30 is in the locked state, the expansion tube 20 is connected to the central tube 10 through the locking mechanism 30, thereby indirectly fixing the expansion tube 20 to the central tube 10, and thus allowing it to be lowered into the wellbore along with the central tube 10. When the locking mechanism 30 is in the unlocked state, the locking mechanism 30 separates from the expansion tube 20, and the expansion tube 20 expands and tightens, securing itself inside the damaged casing and remaining in the wellbore. In subsequent operations, the central tube 10 can drive the locking mechanism 30 upwards.

[0042] The expansion cone 40 is located above the reduced diameter section 21. In other words, the reduced diameter section 21 is located below the expansion cone 40. The expansion cone 40 is inserted into the expansion tube 20. As the expansion cone 40 is driven to move downward, it will drill into the reduced diameter section 21 and expand the reduced diameter section 21 to increase its diameter. Finally, the reduced diameter section 21 is tightened and fixed inside the damaged sleeve after expansion. At this point, the repair work on the damaged sleeve is actually completed.

[0043] The plurality of annular plugs 51 are slidably sleeved outside the central tube 10, thereby enabling them to move axially along the central tube 10 under the drive of an external force (e.g., hydraulic force, as described below). In this embodiment of the invention, the plurality of annular plugs 51 are spaced apart along the axial direction of the central tube 10, that is, two adjacent annular plugs 51 do not contact each other.

[0044] In this embodiment of the invention, the cylinder body 52 is a cylindrical structure open at both ends. The cylinder body 52 is fitted over the central tube 10, forming an annular gap between the cylinder body 52 and the central tube 10. Both ends of the cylinder body 52 form annular ports with the central tube 10; that is, each end of the cylinder body 52 forms an annular port with a corresponding portion on the central tube 10. The cylinder body 52 is not directly connected to the central tube 10; instead, both ends of the cylinder body 52 are connected to corresponding annular plugs 51, thus indirectly achieving connection with the central tube 10. Because the annular plugs 51 slide in conjunction with the central tube 10, the cylinder body 52 and the two annular plugs 51 connected thereto form a driving mechanism capable of sliding along the central tube 10 as a whole.

[0045] Each annular port is sealed by an annular plug 51. The central tube 10, two adjacent annular plugs 51, and the cylinder 52 located between the two adjacent annular plugs 51 form a hydraulic cavity 01. The hydraulic cavity 01 includes a first sub-cavity 011. The central tube 10 has a first fluid passage 02, and the first sub-cavity 011 is connected to the cavity 03 of the central tube 10 through the first fluid passage 02. In this structure, if the pressure of the working fluid in the cavity 03 of the central tube 10 increases, the working fluid with higher pressure will enter the first sub-cavity 011 through the first fluid passage 02, thereby driving the aforementioned drive mechanism downward.

[0046] Among the multiple annular plugs 51, the lowest annular plug (which can also be considered the deepest annular plug in the wellbore) 51 is connected to the expansion cone 40, thus establishing the connection between the drive mechanism and the expansion cone 40. It should be noted that, in this text, the expansion cone 40 is an annular structure and is slidably fitted onto the central tube 10. As described above, the expansion cone 40 is driven downwards. After the working fluid enters the first sub-cavity 011, the working fluid pushes the drive mechanism downwards, which in turn pushes the expansion cone 40 into the reduced-diameter section 21, thereby expanding the expansion tube 20.

[0047] In this embodiment of the invention, when a working fluid (e.g., water) at a preset pressure is introduced into the cavity 03 of the central tube 10, the working fluid can enter the first sub-cavity 011 through the first fluid passage 02, and push the multiple annular plugs 51 and the cylinder 52 downward along the central tube 10, thereby causing the expansion cone 40 to extend to the reduced diameter section 21 and expand the reduced diameter section 21 to tighten and fix it to the inner wall of the damaged casing. In this case, the expanded reduced diameter section 21 is essentially lined with the inner wall of the damaged casing in an interference fit.

[0048] The working process of the sleeve repair tool disclosed in this embodiment of the invention is as follows:

[0049] The casing repair tool is connected to the lowering equipment (such as drilling equipment) through the central tube 10 and is lowered into the wellbore under the drive of the lowering equipment until the reduced diameter section 21 of the expansion tube 20 is lowered to the damaged casing. Then, the surface is pressurized to increase the pressure of the working fluid in the central tube 10 to the preset pressure. The working fluid that reaches the preset pressure can enter the first sub-cavity 011 through the first fluid passage 02 and push the drive mechanism formed by multiple annular plugs 51 and cylinder 52 to move downward. The downward movement of the drive mechanism will drive the expansion cone 40 to move downward, which will cause the expansion cone 40 to drill into the reduced diameter section 21 and expand the reduced diameter section 21. Finally, the expansion tube 20 is expanded and tightened and fixed to the inner wall of the damaged casing.

[0050] Next, the locking mechanism 30 is switched to the unlocked state, thereby separating the locking mechanism 30 from the expansion tube 20, ultimately allowing the central tube 10 to be pulled out of the wellbore by the lowering equipment. This process leaves the expansion tube 20 inside the damaged casing, achieving the purpose of repairing the damaged casing (which is also the casing to be repaired).

[0051] It should be noted that the embodiments of the present invention do not limit the specific value of the preset pressure. Those skilled in the art can set the value of the preset pressure according to parameters such as well conditions and the specifications of the casing repair tool.

[0052] As can be seen from the above working process, the casing repair tool disclosed in this embodiment of the invention repairs the damaged casing by replacing the damaged casing with an expansion tube 20 after expansion. At the same time, the expansion tube 20 is connected by a locking mechanism 30 installed on the central tube 10 located inside the expansion tube 20. In this case, the expansion tube 20 does not need to be connected to other components of the casing repair tool by threaded engagement during the lowering process. This means that the expansion tube 20 does not need to have a large wall thickness to ensure the stability of the threaded connection. This casing repair tool with this structure allows for a smaller wall thickness of the expansion tube 20. After the expansion tube 20 expands and tightens to the inner wall of the damaged casing, the expansion tube 20 can form a larger inner diameter. This prevents the inner diameter of the newly formed wellbore from decreasing significantly at the expansion tube 20, which is more beneficial for some old wells that need to be lowered with larger tools for subsequent operations and mining.

[0053] In this embodiment of the invention, the structure of the central tube 10 can be varied. For example, the central tube 10 can be a single, integral tube (e.g., a single steel pipe). In other embodiments, the central tube 10 may include multiple central tube segments 11 and connecting sleeves 12. Two adjacent central tube segments 11 can be fixedly connected to both ends of the connecting sleeve 12 by threaded engagement. Two adjacent central tube segments 11, two adjacent annular plugs 51, and the corresponding cylinder body 52 form a hydraulic cavity 01. This split structure facilitates the manufacturing of the central tube 10 and allows for more flexible replacement of a damaged central tube segment 11 without replacing the entire central tube 10, which helps reduce the maintenance cost of the central tube 10.

[0054] In a further embodiment, the outer wall of the connecting sleeve 12 disclosed in this embodiment of the invention may be provided with a support protrusion 13. The support protrusion 13 is located in the corresponding hydraulic cavity 01 and slides in cooperation with the inner wall of the corresponding cylinder 52. During the specific driving process, as the cylinder 52 and the two annular plugs 51 connected thereto slide along the central tube 10, the annular plugs 51 slide along the axial direction of the corresponding central tube segment 11, while the cylinder 52 slides relative to the support protrusion 13 along the axial direction of the central tube segment 11. The support protrusion 13 can provide support for the cylinder 52 without affecting the sliding of the cylinder 52, thereby improving the sliding stability of the cylinder 52 and the two annular plugs 51 connected thereto, which is beneficial to the stable driving of the expansion cone 40.

[0055] The structure of the support protrusion 13 can be varied. In one embodiment, the support protrusion 13 can be a short strip-shaped protrusion extending axially along the central pipe segment 11.

[0056] In another embodiment, the support protrusion 13 may be an annular protrusion extending circumferentially along the connecting sleeve 12, and the support protrusion 13 divides the hydraulic cavity 01 into the first sub-cavity 011 mentioned above and a second sub-cavity 012 located above the first sub-cavity 011. A second fluid passage 04 is provided on the annular plug 51 or cylinder 52 located above the second sub-cavity 012, and the second fluid passage 04 communicates with the second sub-cavity 012. In this structure, the support protrusion 13 not only provides support but also divides the hydraulic cavity 01 into the first sub-cavity 011 and the second sub-cavity 012. The volume of the first sub-cavity 011 is smaller than that of the hydraulic cavity 01, which facilitates the working fluid entering the smaller first sub-cavity 011 during operation, allowing it to fill quickly and achieve a more rapid driving effect. Specifically, the first sub-cavity 011 and the second sub-cavity 012 are isolated from each other, and the support protrusion 13 is part of the central tube 10 and therefore will not move. This structure makes it easier for the working fluid entering the first sub-cavity 011 to drive the aforementioned drive mechanism downward.

[0057] During the specific operation, as the working fluid enters the first sub-cavity 011 and drives the corresponding annular plug 51 and cylinder 52 downward, the volume of the first sub-cavity 011 gradually increases. Correspondingly, the volume of the second sub-cavity 012 gradually decreases. The second fluid passage 04 connects the second sub-cavity 012 with the external environment, thereby enabling timely supply of working fluid in and out of the wellbore to balance the pressure in the second sub-cavity 012 and prevent excessive pressure in the second sub-cavity 012 from affecting the downward movement of the annular plug 51 and cylinder 52.

[0058] After the damaged sleeve is repaired, the annular plug 51 and cylinder 52 will move upward along the central tube 10, thereby resetting and preparing for the next repair work. During the upward movement of the annular plug 51 and cylinder 52, the first sub-cavity 011 gradually decreases in size, and the second sub-cavity 012 gradually increases in size. The second liquid passage 04 connects to the external environment to balance the pressure in the second sub-cavity 012, thus avoiding the problem of excessive pressure in the second sub-cavity 012 making it difficult for the annular plug 51 and cylinder 52 to move upward. Similarly, during this process, the first liquid passage 02 can also balance the pressure in the first sub-cavity 011, making it easier for the annular plug 51 and cylinder 52 to move upward.

[0059] As described above, the annular plug 51 can seal the annular port between the end of the central tube 10 and the cylinder 52. To prevent excessive movement of the cylinder 52 and the connected annular plug 51 during upward or downward movement, in a further embodiment, the support protrusion 13 can be engaged with an adjacent annular plug 51 in a first direction, and similarly, the support protrusion 13 can be engaged with an adjacent annular plug 51 in a second direction. Specifically, the first direction is the downward direction of the cylinder 52 and the connected annular plug 51. The second direction is the upward direction of the cylinder 52 and the connected annular plug 51. It should be noted that the first direction and the second direction are opposite and both are parallel to the axial direction of the central tube 10. The adjacent annular plug 51 and the adjacent annular plug 51 mentioned above refer to one and the other of the two annular plugs 51 that constitute the hydraulic cavity 01 where the support protrusion 13 is located.

[0060] It should be noted that although the support protrusion 13 can limit the movement of the two adjacent annular plugs 51 in two directions, the downward stroke of the two adjacent annular plugs 51 and the cylinder 52 connected to them along the central tube 10 is sufficient to ultimately push the expansion cone 40 into the reduced diameter section 21 of the expansion tube 20, and completely expand the reduced diameter section 21. Those skilled in the art can reasonably design the sliding stroke between them according to the specifications of the specific casing repair tool.

[0061] The support protrusion 13 can be a separate structure from the connecting sleeve 12, and can be fixedly connected by means of threaded engagement, welding, or interference fit. In other embodiments, the support protrusion 13 can be an integral structure with the connecting sleeve 12. An integral structure of the support protrusion 13 and the connecting sleeve 12 reduces on-site assembly operations, and the process of forming an integral structure is relatively mature, facilitating mass production of the connecting sleeve 12.

[0062] In this embodiment of the invention, there are at least two annular plugs 51 and at least one cylinder 52. In one embodiment, there are two annular plugs 51 and one cylinder 52, with the two annular plugs 51 fixed to both ends of the cylinder 52, thereby forming a primary drive mechanism. In another embodiment, there can be at least three or more annular plugs 51. There are at least two or more cylinders 52. Multiple cylinders 52 are axially spaced in the central tube 10, and multiple pairs of adjacent annular plugs 51 block the annular ports at both ends of the cylinders 52 located between them, thereby forming multiple hydraulic chambers 01, which are axially distributed in the central tube 10. Of course, in this case, there are also multiple first liquid passage holes 02 opened in the central tube 10. Each hydraulic chamber 01 can communicate with the lumen 03 of the central tube 10 through at least one first liquid passage hole 02. This structure can form a multi-stage drive mechanism. In the specific working process, the working fluid in the central tube 10 will simultaneously enter the first sub-cavity 011 of multiple hydraulic chambers 01, thereby realizing the simultaneous downward movement of the multi-stage drive mechanism, and finally the combined force drives the expansion cone 40. Because this structure has a large driving force, it is more conducive to the expansion cone 40 to expand the diameter of the constriction section 21.

[0063] In this embodiment of the invention, the locking mechanism 30 can be a hydraulic anchor. Of course, the locking mechanism 30 can also be other structures that switch between unlocked and locked states by changing its diameter; this embodiment of the invention does not limit the specific type of locking mechanism 30. The locking mechanism 30 is fixed to the bottom end of the central tube 10. After the repair work is completed, the central tube 10 drives the locking mechanism 30 upwards. The locking mechanism 30 will hook onto the expansion cone 40, thereby driving the expansion cone 40 upwards as well, and finally, they are lifted to the ground by the lowering device.

[0064] To facilitate connection with the lowering device, the sleeve repair tool disclosed in this embodiment of the invention may further include a connector 60, which is fixedly connected to the central tube 10 via a threaded connection. Specifically, one end of the connector 60 is fixedly connected to the central tube 10 via a threaded connection, and the other end of the connector 60 is used to connect to the lowering device via a threaded connection.

[0065] In this embodiment of the invention, the annular plug 51 and the cylinder body 52 can be fixedly connected by welding or by threaded connection. In one embodiment, the plurality of annular plugs 51 are fixedly connected to the corresponding cylinder body 52 by threaded connection.

[0066] In this embodiment of the invention, the expansion cone 40 can be directly connected to the lowermost annular plug 51, or indirectly connected to the lowermost annular plug 51. In one embodiment, the sleeve repair tool disclosed in this embodiment of the invention may further include a cone seat 70. The cone seat 70 can be sleeved outside the central tube 10 and connected to the lowermost annular plug 51, and the expansion cone 40 can be mounted on the cone seat 70.

[0067] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A casing repair tool, characterized in that, Includes a central tube (10), an expansion tube (20), a locking mechanism (30), an expansion cone (40), multiple annular plugs (51), and a cylinder (52); wherein: The plurality of annular plugs (51) are slidably sleeved outside the central tube (10) and are spaced apart along the axial direction of the central tube (10); The cylinder (52) is sleeved outside the central tube (10), and both ends of the cylinder (52) form annular ports with the central tube (10). Each annular port is blocked by annular plugs (51). The central tube (10), two adjacent annular plugs (51), and the cylinder (52) located between the two adjacent annular plugs (51) form a hydraulic cavity (01). The hydraulic cavity (01) includes a first sub-cavity (011). The first sub-cavity (011) is connected to the lumen (03) of the central tube (10) through a first liquid passage (02) opened on the central tube (10). Among the plurality of annular plugs (51), the lowest annular plug (51) is connected to the expansion cone (40), and the expansion cone (40) is slidably sleeved on the central tube (10); The reduced diameter section (21) of the expansion tube (20) is located below the expansion cone (40), and the expansion tube (20) is connected to the central tube (10) through the locking mechanism (30) in a locked state; When a working fluid with a preset pressure is introduced into the cavity (03) of the central tube (10), the working fluid can enter the first sub-cavity (011) through the first liquid passage (02) and push the plurality of annular plugs (51) and cylinder (52) down along the central tube (10) to drive the expansion cone (40) to extend to the reduced diameter section (21) and expand the reduced diameter section (21) so that it is tightened and fixed to the inner wall of the sleeve to be repaired.

2. The sleeve repair tool according to claim 1, characterized in that, The central tube (10) includes multiple central tube segments (11) and connecting sleeves (12). Two adjacent central tube segments (11) are fixedly connected to the two ends of the connecting sleeves (12) by threaded engagement. Two adjacent central tube segments (11), two adjacent annular plugs (51), and the corresponding cylinder body (52) form the hydraulic cavity (01).

3. The sleeve repair tool according to claim 2, characterized in that, The outer wall of the connecting sleeve (12) is provided with a support protrusion (13), which is located in the corresponding hydraulic cavity (01) and slides in cooperation with the inner wall of the corresponding cylinder (52).

4. The sleeve repair tool according to claim 3, characterized in that, The support protrusion (13) is an annular protrusion extending circumferentially along the connecting sleeve (12). The annular protrusion divides the hydraulic cavity (01) into a first sub-cavity (011) and a second sub-cavity (012) located above the first sub-cavity (011). The annular plug (51) or the cylinder (52) located above the second sub-cavity (012) is provided with a second liquid passage hole (04) communicating with the second sub-cavity (012).

5. The sleeve repair tool according to claim 3, characterized in that, The support protrusion (13) is engaged with an adjacent annular plug (51) in a first direction, and the support protrusion (13) is engaged with another adjacent annular plug (51) in a second direction, the first direction being opposite to the second direction.

6. The casing repair tool according to claim 3, characterized in that, The supporting protrusion (13) and the connecting sleeve (12) are an integral structure.

7. The sleeve repair tool according to claim 1, characterized in that, There are at least three annular plugs (51) and at least two cylinders (52), which are distributed at intervals along the axial direction of the central tube (10). Multiple pairs of adjacent annular plugs (51) block the annular ports at both ends of the cylinders (52) located between them, and form multiple hydraulic chambers (01). The central tube (10) has multiple first liquid passage holes (02) that are respectively connected to the multiple hydraulic chambers (01).

8. The casing repair tool according to any one of claims 1-7, characterized in that, The locking mechanism (30) is a hydraulic anchor.

9. The casing repair tool according to any one of claims 1-7, characterized in that, The sleeve repair tool also includes a connector (60), which is fixedly connected to the central tube (10) by a threaded connection.

10. The casing repair tool according to any one of claims 1-7, characterized in that, The plurality of annular plugs (51) are fixedly connected to the corresponding cylinder bodies (52) by threaded connection.

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